To do hardware accelerated video decoding on sunxi devices nowadays, you don't need any software provided by Allwinner, which is either (partly) closed sourced and/ or violating the GPL. Instead you should use the result of the community's reverse engineering work, called Cedrus.

As this is only proof of concept code, the goal is a mainlined video engine driver in the end. To take full advantage of such a driver, the other bits (display, hdmi, sound ...) also have to be rewritten in ongoing mainline process.

Hardware registers

The closed source blob uses direct access to hardware registers using mmap to userspace. Currently known register usage is documented: